1. Field
The described technology relates generally to an organic light emitting diode (OLED) display.
2. Description of the Related Art
An organic light emitting diode display includes two electrodes and an organic emission layer interposed therebetween, electrons injected from a cathode that is one electrode and holes injected from an anode that is another electrode are bonded to each other in the organic emission layer to form an exciton, and light is emitted while the exciton discharges energy.
Each pixel of the organic light emitting diode display includes a switching thin film transistor, a driving thin film transistor, a capacitor, and an organic light emitting diode. A driving voltage ELVDD is supplied from a driving voltage line to the driving thin film transistor and the capacitor, and the driving thin film transistor serves to control the current flowing to the organic light emitting diode through the driving voltage line. A common voltage line supplies a common voltage ELVSS to the cathode and forms a potential difference between a pixel electrode as an anode and a common electrode, thereby causing a current between the pixel electrode and the common electrode.
The common voltage ELVSS is transmitted to the common electrode formed on barrier ribs by continuous contact among a gate common voltage contact unit including gate lines, a data common voltage contact unit including data lines, and the common electrode, which are formed in a peripheral region.
However, because of a thickness of the barrier rib, a developer is not sufficiently vaporized so a lifting phenomenon may be generated at a border of a contact hole formed in the barrier rib.
Regarding the lifting phenomenon, a common electrode provided on the barrier rib is passed through the contact hole to deteriorate adherence with a bottom metal film and generate heat.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.